1. Fields of the Invention
The present invention relates to a method for estimating a 3D vector angle from a 2D face image, a method for creating a face replacement database, and a method for replacing a face image, and more particularly, to the method with the effect of replacing a face image by detecting a rotation angle of the face image and then replacing a region to be replaced of the face image by a replaced image.
2. Descriptions of Related Art
Face replacement technology gains more attentions in recent years, primarily due to its wide scope of applicability in the fields of movies, entertainments and medical cosmetology. For example, when a movie is shot, a stuntman's face image is replaced by a main actor's face image, so that the main actor no longer needs to perform an action of high level of difficulty, and a cameraman needs not to avoid the angle of shooting at the stuntman's face. Such face replacement technique can ensure the safety of the main actor and improve the efficiency of shooting the film and saving the production cost effectively. In the aspect of entertainment, users may replace faces with others to achieve the effect of having fun. In the aspect of medical cosmetology, patients requiring a plastic surgery may observed the result of the surgery ahead of time before deciding whether or not to take the surgery in order to avoid unexpected results.
In a conventional face replacement technique, the feature points of an image to be replaced and a target image are calculated manually, so as to designate a region and an angle to be replaced, and then the range of the calculated feature points of the target image is replaced by a range of calculated feature points of the replaced image. However, this technique is applicable for the replacement of a single static image only, but is difficult to be applied for replacing dynamic images. In addition, it is necessary to manually mark the feature points of the image to be replaced and the target image, and thus the operation is inconvenient to users and time-consuming. Color difference may occur at the boundary of the replaced image easily, and thus the overall visual perception of the replaced image is unnatural. Furthermore, the method of estimating a face angle applied in the replacement process is too complicated and takes lots of computation time. Therefore, this technique fails to provide a quick image replacement.
In view of the aforementioned problems, the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally designed a face replacement technique in accordance with the present invention to overcome the aforementioned problems of the prior art.